As Nokia, the erstwhile smartphone leader, fails to gain much headway on Apple and Samsung Electronics, the Finnish company is setting its sights on a weaker rival: BlackBerry.

Nokia is betting its partnership with corporate computing giant Microsoft will help it win business users, targeting BlackBerry's stronghold. Nokia's newest Lumia smartphones, including two introduced this week at the Mobile World Congress in Barcelona, run on Microsoft's operating system and come with Excel, Word and PowerPoint.

Gaining a foothold in the business market is crucial for Nokia as it fights BlackBerry for third place in smartphones, behind Samsung, the leader in devices using Google's Android, and Apple. Shares of Nokia and BlackBerry have lost 90 per cent in the past five years as consumers and companies have turned to Android and Apple's iOS.

"The importance of winning the business audience on a scale of one to 10 is easily an 11," said Ramon Llamas, an analyst at US research firm IDC. Llamas said he expected Windows Phone handsets to surpass BlackBerry this year, with Nokia responsible for most of the gains.

BlackBerry, formerly known as Research In Motion, pioneered the corporate mobile device market in North America and still has a strong following in Washington and on Wall Street.

Nokia, the biggest seller of Windows handsets, may appeal to information-technology chiefs seeking easy synchronisation between smartphones and company computers, which most often use Microsoft's operating system.

Nokia's chief executive Stephen Elop, who joined from Microsoft in 2010, started betting on his former employer's operating system after Nokia's homegrown Symbian software fell out of favour among consumers.

The importance of winning the business audience on a scale of one to 10 is easily an 11

Lumia unit sales rose to 4.4 million in the fourth quarter, making up almost 75 per cent of all Windows Phone sales. BlackBerry sold 7.4 million smartphones, for 3.2 per cent of the global market. Android devices and iPhones account for about 90 per cent of smartphone sales.

Elop said he often got asked whether he would be interested in buying BlackBerry, even though the company has not said it is for sale. "When I get asked that question, my answer is: 'I'm interested in their customers'," he said in Barcelona this week. "It's a really perfect moment to go after that marketplace."

Businesses are important to handset manufacturers because they carry a lot of clout when carriers decide which handsets to offer. A single corporate account can include thousands of individual users who tend to favour more expensive devices and have higher phone bills. Nokia says one European carrier it is negotiating with receives about a third of its revenue from companies.

Nokia has been touting its business-customer gains. The company says Coca-Cola salespeople in Cambodia and Vietnam use Lumia smartphones to process orders while on the move. London real-estate agent Foxtons equipped more than 900 employees with Lumias, allowing them to synchronise calendars and work on spreadsheets and documents on the road.

BlackBerry delayed its new operating system, BlackBerry 10, several times. Next month, it plans to start US sales of the US$199 touch-screen Z10, which Bloomberg's Rich Jaroslovsky called "handsome, intuitive to use and a whiz at multi-tasking".

The company has more than 250,000 enterprise servers around the world, which help it ensure the security of corporate communications. It says more than 3,500 companies and government agencies in North America are considering its latest devices.

David Smith, BlackBerry's executive vice-president for mobile computing, said: "It's not surprising that competitors are scrambling to get into the enterprise."